P0987

SYMPTOM
P0987 - 4C HYDRAULIC PRESSURE TEST FAILURE

WHEN MONITORED
In any forward gear with engine speed above 1000 RPM shortly after a shift and every minute thereafter.

SET CONDITION
After a shift into a forward gear, with engine speed, 1000 RPM, the TCM momentarily turns on element pressure to the clutch circuits that don't have pressure to identify the correct pressure switch closes. If the pressure switch does not close 2 times the DTC sets

POSSIBLE CAUSES
- RELATED LINE PRESSURE DTC'S PRESENT
- RELATED SPEED RATIO AND/OR PRESSURE SWITCH DTC PRESENT
- POOR LINE PRESSURE SENSOR CONNECTION
- TCM AND WIRING - LOW LINE PRESSURE
- INTERMITTENT WIRING AND CONNECTORS
- 4C PRESSURE SWITCH SENSE CIRCUIT OPEN
- 5-VOLT SUPPLY CIRCUIT OPEN
- TRANSMISSION CONTROL RELAY OUTPUT CIRCUIT OPEN
- 4C PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
- 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
- 4C PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
- EXCESSIVE DEBRIS IN OIL PAN
- INTERNAL TRANSMISSION - 4C PRESSURE TEST
- TCM - 4C PRESSURE SWITCH
- TCM - NO 5 VOLTS LOW LINE PRESSURE SENSOR